The Aaron Memorial Lens

While star-testing a number of Nikon-mount lenses, I was surprised to find one that was conspicuously sharper than the rest. It is the lens of the Nikkormat that my uncle, the late Ira E. Aaron, gave me in the 1980s because he wasn't using it.

On my Nikon D5500, this lens is sharp. It is a Nikkor-H 50-mm f/2, a conventional 6-element design, very precisely made. I've learned that in its own time, it was nicknamed the "Japanese Summicron" as the only competitor to an extremely expensive Leica lens. The Nikkor-HC version, multicoated, would supposedly be better, but the single-layer coating on the one I have is very effective.

This is a pre-AI lens, so it only fits Nikons whose AI tab either folds down (like my F3) or retracts when pressed (like my D5300 and D5500), or which are as old as the lens itself. Nikon connoisseurs can of course get it "AI'd" to fit the whole range of cameras.

This lens is going to be used regularly for astrophotography. I'm going to call it the Aaron Memorial Lens. The serial number tells me it was made in 1971, which was a very important year for me (the first year of high school). I'm glad to have it live on as a memorial to my uncle.

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Starlink satellites

In this picture you see the trails of many of the first batch of 60 satellites recently launched by Elon Musk's enterprise, plus the trail of one unrelated satellite. (Single 30-second exposure, Nikon D5500, Aaron Memorial Lens, 50-mm at f/2.8.) What I actually saw through 10×42 binoculars was quite different — I saw a couple of dozen (or more) 9th- to 5th-magnitude stars moving in a line, although the trail shows that their actual motion was not exactly parallel to the line they were arranged in. I couldn't see them with the unaided eye in town, but they produced plenty of UFO reports from out in the country.

These were the first 60 of a proposed constellation of 12,000 satellites that will provide worldwide Internet service. It is not yet clear whether worldwide public opinion will actually allow Elon Musk to put the rest of them in orbit. The reason is that they may end up being a menace to astronomy, or at least spoiling people's view of the night sky.

There are about 5,000 satellites in orbit now, many of which are rather bright but useless (spent rocket boosters and the like). These are smaller and fainter, but one is still daunted by the proposed quantity of new satellites — there might be no part of the sky that is not aswarm with them. What we're not sure about is how much time they will spend in the earth's shadow (where they're not a problem) and how bright they will be. They may bother astronomers at higher latitudes even if they're not a problem at the equator.

Let me add something else: It's not just whether astronomers can still do their research and get decent pictures. It's whether ordinary people will still get to enjoy the sky the way it has been since remote antiquity. "They dug up all the trees and put 'em in a tree museum," to quote a Joni Mitchell song. Let's not do that to the stars. We don't want to take away ordinary people's view of the sky, worldwide, even if astronomers have ways to work around the problem.

The Outer Space Treaty of 1967 provides for international "consultation" when one nation's space activities risk interfering with other nations' research, including ground-based astronomy. That might provide a legal framework for challenging the project. The American Astronomical Society is already expressing concern. We don't know how serious a problem it will be because most of us do not have reliable information about brightness and the effect of the earth's shadow. Musk has even expressed willingness to paint the satellites black to reduce their visibility.

But let's be cautious. And while we're at it, can we devise a way to remove some of the brighter satellites that are up there and not working? Space is not our junkyard.

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Markarian's Chain with a 50-mm lens

[Updated.]

I like to probe the limits of astrophotographic equipment. This is a small area of a larger photograph taken with the same 50-mm lens at f/2.8, a stack of 10 30-second exposures at ISO 200 with the camera on my iOptron SkyTracker. You can see Markarian's Chain of galaxies (scroll down to May 6 for a much better picture). It's not great, but it's remarkable that it's possible at all.

The picture shows stars to magnitude 13.4 and galaxies to magnitude 13.0. It doesn't show them well, but it shows them.

Now I know that if I have to photograph faint galaxies (or comets, or some such) with only a 50-mm lens, I can do it. Also, if I can do this, the same lens and technique will give outstanding views of the Milky Way later in the summer.

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Memorial Day and wrong expectations

I am profoundly grateful for the people who risked, and in many cases lost, their lives to secure my freedom. I agree wholeheartedly with those who point out that Memorial Day should never be understood as just the holiday that marks the beginning of summer. It is our national day of remembrance.

But this year I got tired of being told that I wasn't being somber enough. From different directions I heard that one shouldn't shop, one shouldn't even picnic, and I actually saw someone threaten violence if people didn't observe the minute of silence at 3 p.m. that he imagined was required by law.

What's wrong with enjoying some of our hard-won freedom? Memorial Day is not just a day of mourning — it is also a day of thanksgiving. Let's be thankful and enjoy being free.

Some are offended by Memorial Day sales. Well, I agree that it would be in better taste if merchants did something to explicitly honor our war dead, such as statements in advertisements, flags on stores, or the like. Some do, some don't.

But let me explain why there are sales on Memorial Day. For many full-time workers, Memorial Day is a valuable opportunity to catch up on shopping. They're off work on a weekday. And because there are more shoppers, merchants can offer lower prices. Why shouldn't they say so? In fact, can a merchant honor our war dead by giving people lower prices? If not, why not?

By the way, as it happens, I did not observe the 3 p.m. minute of silence. I was busy working — for a defense contractor — on scientific research to help defend the United States.

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A grand time

We've been off visiting the grandchildren again...

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On teaching children about electricity and electronics

While there, we were going to work through some of the projects in a book about electricity that their parents found, but we quickly abandoned it and did a project of my own design instead. It lights up two LEDs. They were fascinated.

I don't claim to be an expert on teaching preschool science (although, really, it isn't any harder than teaching graduate school). But I do have a few thoughts, partly inspired by the book that we abandoned (and which I shall not name).

There's no point in doing a project unless the children learn how it works. "Put these things together, and voilà, magic happens!" is not a good kind of project.

With this one, the concepts to be taught include the following. You don't have to teach all of it, of course, but here's the whole kaboodle:

• Electricity is the flow of electrons through wires and other things.
• The electrons come out of the battery, give up part of their energy as they pass through things, and go back into the battery. If you interrupt their path at any point, they stop flowing.
• When electrons go through an LED, it lights up.
• There is also a resistor to take away more of the energy, because the electrons come out of the battery with more energy than the LEDs can handle.
  
  My resistor was 1000 ohms, 1/4 watt. Some variation is possible. Use 270 ohms if you are using three AA cells as described later.
• It doesn't matter in what order the electrons go through the different parts of the project. The resistor, red LED, and green LED can be in any order as long as every electron goes through all of them. Each of them takes up some of the electrons' energy. (Kirchhoff's Voltage Law and Kirchhoff's Current Law, and no, I didn't introduce those names.)
• Electrons can only flow through an LED in one direction. If one or both of the LEDs are backward, the electrons don't flow, and nothing lights up.
  
  The shorter of the two wires coming out of the LED is usually the one that should be toward the positive terminal of the battery, if I remember right.

Now for some practical notes:

• We ditched the book partly because it had children handling a lithium coin cell and button-sized neodymium magnets, both of which are potentially lethal when swallowed.
• I like LEDs because not much can go wrong except that you can easily ruin them, and they are cheap. They don't get hot or require dangerous voltages.
• Wire nuts of the smallest size are good for helping you twist wires together and hold them. You see blue wire nuts in the picture.
• Using a 9-volt battery wasn't ideal, but it's what I had. The problem with a 9-volt battery is that if there are two, children are tempted to join them by their contacts, which creates a short circuit with the energy of both batteries, which will heat up and burst. If children experiment with a 9-volt battery, there should be just one battery, and it should not be lithium, and preferably not even alkaline.
• It would probably be better to use, as a general-purpose power source, three AA cells (alkaline OK, not lithium) in series in a battery holder.
  
  (The No. 6 Dry Cells of 1950s science books are long gone, and anyhow, they can deliver so much current that I'm not sure I consider them safe. Yes, at 1.5 volts they can't shock you, but if short-circuited, they would deliver 25 amps, or 37.5 watts, which is enough to give off a lot of heat.)
• Projects involving building motors or electromagnets are problematic. They require a lot of energy. We didn't do any projects of that type. But a few AA cells will power an electromagnet for a short time if you make it with dozens if not hundreds of turns of wire around a nail.

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Moon without EFCS

The Daily Notebook is still alive, and so am I. I've just been busy!

The Nikon D5500 does not have Electronic First-Curtain Shutter (EFCS) (what Canon calls Live View Silent Shooting). With mirror lock and exposure delay enabled, does it need it? Apparently not; at least, this picture is just as sharp as what I saw in live view. Single 1/800-second exposure, AT65EDQ 6.5-cm f/6.5 refractor.

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DG EX is not the same as EX

Many of you know how much I rely on my Sigma 105-mm f/2.8 DG EX lens (for Canon).

Having tested them side by side, I now know the DG EX version of the lens is better than the earlier EX (not DG) version. It has one more element, and it's sharper at the edges and corners.

I presume the even newer DG EX OS version would be better yet.

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Opinions or just loyalties?

I keep encountering people with strong political loyalties but no political opinions at all.

They know whose side they're on (person or party) but have never looked at any issue, gathered the facts, and thought it through.

Instead they have just taken sides like rooting for a football team. Once they choose a side, they don't question it.

Such people often have mental images, which they mistake for facts. But a mental image is only imagination, perhaps aided by a glance at a headline, and may or may not be realistic as far as it goes. It's not accompanied by checking facts.

Don't be that kind of person.

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More galaxies than you can count

There are at least 40 galaxies visible in this picture; I didn't finish counting. The brightest one, on the left a little below center, is M87; the curved row of bright ones higher up in the picture is Markarian's Chain. Among the stars (or rather far beyond them) are quite a few other galaxies visible as fuzzy objects. Some are indistinguishable from stars; for example, the two dots that seem to be coming out of M87 at the lower right are actually two of its satellite galaxies.

[Update:] Here's the same picture with many (not all!) of the galaxies labeled by nova.astrometry.net.

Stop for a moment and let this sink in: Those fuzzy objects are galaxies. The larger ones are comparable to the one we live in; that is, if you were inside one of them, its stars would comprise almost everything you see in the night sky, just as the stars of our galaxy do as seen from earth. The smaller ones, though not as large as the galaxy we live in, are still larger than you can visualize. And many of them look small in the picture because they are distant, not small; you can see spiral arms in several.

The second thing to let sink in is that this is a total of 32 minutes exposure through a telescope two and a half inches in diameter. The efficiency of good digital cameras is amazing. In the 1950s, a picture like this (reaching at least magnitude 18) would require a large observatory telescope and an exposure time measured in hours.

Stack of eight 4-minute exposures, AT65EDQ 6.5-cm f/6.5 refractor, Nikon D5500 (Hα modified), autoguided on Celestron AVX mount, color image presented as monochrome.

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And another contentious moral issue

It has been more than ten years since I wrote about the abortion controversy (reviewing a book by Francis Beckwith).

I recently rewrote a paper that I originally presented in 1979 to the Yale Socratic Club (a short-lived discussion group modeled on a similar club at Oxford). You can read it by clicking here. Because of its length, I'm presenting it as a PDF file, not a Notebook entry.

What may interest you about this paper is that it is not a presentation of religious doctrine. An atheist who believes in human rights could accept all of my reasoning.

I'm not wanting debate; much less do I want hate mail. Experience has shown me that people who disagree about this issue often respond with strong expressions of contempt that contain no real reasoning. That's not where I'm heading with this.

If you are convinced that you've found a substantial problem with my reasoning or my claims of fact, consider writing to me, but I don't promise to reply. Truth is not found by contests of debating skill.

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Artificial intelligence ethics: a checklist

To see my April 30 entry about integrated flux nebulosity, click here. Today I'm going to address some ethical matters.

The other day I wrote about new developments in artificial intelligence and possible hazards. If you haven't read that entry, you may want to read it before proceeding.

I promised you a further disquisition about artificial intelligence and ethics, so now I need to deliver. But I can't write a whole book about it right here, and it deserves several books. I am gratified that people are starting to be concerned and are no longer so eager to just trust computers to do the right thing.

What I can offer you here is little more than a checklist of possible issues, but that's probably a useful start. As I've said before, the biggest danger of AI, in my opinion, is that people so easily think machines are much more humanlike than they are. Just a bit of humanlike behavior, especially recognition and production of human language, seems to be all it takes to make some people believe a machine is thinking, feeling, and deserving of trust. Not so! Machines are machines. And anyhow, if it really is thinking and feeling, doesn't that mean you shouldn't trust it?

Here is a short checklist of other issues to watch for.

• Real-time safety in automated activities such as driving, piloting aircraft, and administration of medical treatment. There is no sharp line between AI and other automatically or semiautomatically controlled equipment. Things can go wrong. Remember Therac.
• Good old-fashioned information security. Is Alexa or "Hey Google" spying on you? Could it be, if someone tampered with the software? There are also "big data" security issues, not because of AI but because we are putting more information about our daily lives into computers. Notoriously, people assume that the machines and the people who build them are perfectly benevolent and sinless.
• Accidentally destructive or nonconsensual use of legitimately acquired information. One example has to do with face recognition. People don't object to security cameras in public places — in fact they're usually clearly beneficial. But what happens when someone runs a face recognition program on the video (in real time or recorded) and comes up with a list of who was where when, and then puts the information to use? And who is liable if a mistaken face recognition algorithm (yes, they make mistakes) causes a false arrest?
• Deliberately destructive or malicious use of AI. If our army can use AI, so can enemies and terrorists. AI doesn't require enormous computers that only the Pentagon can afford. And organized crime can use AI too. Already we are seeing more sophisticated faking of telephone calls and e-mail. And what about AI-assisted editing of speech and video to produce a realistic movie of a real person saying or doing something he or she never said or did?
• Institutionalized discrimination. In a society with a history of racial discrimination, machine learning programs will learn to discriminate, if they are not prevented. The reason? The machine is doing its job. If you tell it to find good customers by figuring out who is more prosperous, it will favor white people because white people are more prosperous, even though we do not want to perpetuate the difference. Simply in the interest of doing business successfully, the machine will perpetuate advantages, even slight ones, that are enjoyed by particular ethnic groups, simply because it hasn't been told not to. The machine doesn't know that certain differences, even if real, should not be used in business decisions because they reflect past injustice.
• Political correctness. It is easy to use AI to implement automatic censorship based on shallow criteria. I'm told that Twitter at one point banned a quotation from Mother Teresa of Calcutta (now St. Teresa) because some such automated censor was somehow triggered. And there is also the issue of people who serve on ethics advisory boards for AI companies and the like: do we allow them to have diverse opinions or require them all to toe exactly the same line?
• Making of ethical decisions by machines. As computers are given more responsibility for making decisions with consequences, we can imagine situations like in 2001: A Space Odyssey where a computer makes, and carries out, a decision that humans see as obviously unethical. We need to think carefully about how much power we given to machines. The notion, carried over from simple accounting systems, that "computers never make mistakes" is simply wrong where AI is involved; AI technology is based largely on computations that are usually but not invariably correct, and anyhow, a computer that has been given the wrong rules to follow will follow them.

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Beware of "anger porn"

Previously published on Facebook.

My Christian friends don't use pornography, or if any of them do, they consider it shameful and don't tell us about it.

But there is something like pornography that a lot of Christians are into. I call it "anger porn" or "hate porn," media whose point is to give you a thrill of anger by telling you how evil somebody else is, how much you should despise what they are doing.

That is absolutely standard fare for a certain kind of political commentary. "The truth shall make you mad" as one commentator proudly puts it.

Closely related are memes that distort the truth to make it more exciting, "to make the right side win" or to rile people up so they will be on "the right side." Or just because they enjoy being riled up.

"Anger porn" often focuses on things that are genuinely bad, just as sexual pornography tries to show genuinely attractive people. But just as the latter discards their humanness, the former discards fair-mindedness, careful justice, and understanding, so that you can wallow in feelings that are not strictly tied to facts.

It is often our duty to object strenuously to what people are doing. That is not the same as despising the people themselves. Not at all.

Everyone, please consider whether your mental diet of political and cultural commentary is degrading you. Have you trained yourself to get a thrill out of despising your fellow humans and playing fast and loose with the truth?

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And beware of shallow Darwinist ethics

Also previously published on Facebook.

I am alarmed at how many of my Christian friends seem to adhere to a naive kind of Darwinian ethics even though they are skeptical about Darwinian biology (evolution).

Darwinian ethics says we are all in a struggle for survival, and losers deserve to lose; that leaves more for the rest of us; don't waste our precious resources trying to help losers.

The Christian view is that we are all totally dependent on the undeserved generosity of God.

And I note in passing that there's a kind of sports fandom that feeds right into Darwinian ethics, the kind where you love seeing the other side lose. There are good reasons to like sports, of course; this isn't one of them.

Think about it.

My biologist daughter reminds me that this is of course not even proper Darwinism. It leaves out population genetics, among other things, and it misdefines "survival of the fittest" as if it meant something other than success at having offspring. Even in Darwin's own time, people tried to turn his theory into a scientific excuse for racism and general heartlessness, and it pained him.

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CBD is medicine, not food

I am glad that CBD oil is becoming more widely available. It is a useful treatment for some neurological disorders and chronic pain. And unlike marijuana, it is not intoxicating because it does not contain THC.

But it is still a drug, not a food. I see no point in putting it into coffee or hamburgers as a "nutritional supplement." We don't do that with Tylenol. We shouldn't do it with CBD.

I suspect that this nonsense may be part of a scheme to create confusion between CBD and recreational cannabis (still illegal in most states). I would much rather see CBD go through the FDA approval process and become a properly regulated medication (even if approved for over-the-counter sales). Then health insurance would cover it!

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